Wood and solid fuel stoves are used in many places throughout the world. They usually comprise a metal fire-box to contain the solid fuel and the flames produced by the burning of the solid fuel. Access to the fire-box for loading of more fuel, and for cleaning and servicing is by a door in the front (or other) panel of the stove. The solid fuel is supported on a grate that separates the fire-box from the ash-chamber, the grate allowing the burning fuel to be fed by air rising from beneath the grate and allowing spent fuel in the form of ash to fall into the ash-chamber to be collected. The collected ash can be disposed of periodically by removing and emptying a collection pan within the ash-chamber.
Most stoves have some type of regulator to control the supply of air into the fire-box. The regulator may be an adjustable shutter or a wheel.
The combustion efficiency of heating stoves can be impaired by intaking air that is relatively cool. Air may be drawn from the immediate surroundings of the stove or even from outside. The air passes through the air regulator and into the fire-box where it is heated during combustion. The hot exhaust gases that are usually vented through a flue and into a chimney are much hotter than the temperature at which the uncombusted air was supplied to the fire. This results in a loss of energy. The efficiency of heating stoves can be improved by pre-heating the air before it is supplied to the fire-box.
In some stoves the air is supplied from a particular source, for example the supply may come from a conduit installed in the floor of a house leading from outside of the house to the bottom of the stove. It is wasteful to provide conduits during the construction of a house that may not be used (if for example a conventional gas or electrically powered fire is subsequently used). However, if such conduits are not supplied, houses without them would be prevented from using stoves which are designed to take in air through such a system.